This Mac tip is provided by Mark Greentree and was originally posted on Mark’s blog – Everyday Mac Support. For more of Mark’s tips visit his site, follow him on Twitter, or browse his archive of posts here.
Did you know that when you hide an application by using Command + H, you can have it appear transparent in the dock as presented in the image above with the mail icon.
In order to do this we will need to use Terminal. To locate Terminal simply navigate Applications > Utilities and within the Utilities folder you will locate Terminal.
Simply launch and then enter the following followed by return:
defaults write com.apple.Dock showhidden -bool YES
Then type the following followed by return:
killall Dock
After successful entry your dock will refresh and the new hidden dock icons will be available to use.
If you decided you do not wish to have your dock in this mode you can simply return it back to the previous settings by doing the following steps:
Simply launch Terminal and then enter the following followed by return:
defaults write com.apple.Dock showhidden -bool NO
Then type the following followed by return:
killall Dock
Warning: Terminal commands have the ability to change the running operation of your Mac. Please copy and paste the Terminal command as shown directly from the article. Mistakes in keystokes can cause your Mac to perform differently and may in-fact result in a loss of data. It is advised that you only use the Terminal if you feel comfortable with the command line interface. If you are ever unsure please consult your local tech support person.